Window blind string controller



FIG. 1 is a perspective view of a window blind string holder;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a left side view thereof; and,

FIG. 8 is a perspective view of the window blind string controller shown in condition of use with broken line environmental structure. The broken line showing of environmental structure is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a window blind string controller, as shown and described. 